Conventionally, there has been known this sort of working machine having a boom configured to perform telescopic motion, such as a mobile crane. This boom includes a plurality of boom members and performs the telescopic motion by shifting next boom members in front of respective ones with respect to the boom members other than a top boom member (see, for example, Patent Literature 1).
In addition, the boom performs the telescopic motion by driving a telescopic cylinder provided in the boom members. Therefore, if an amount of the telescopic motion is increased by, for example, extending the boom from the minimum length to the maximum length, it takes a long time for the telescopic motion of the boom.